Machine for removing the sharp edge in plates in general and in particular in glass plates

ABSTRACT

A machine for removing sharp edge in plates in general and in glass plates in particular, comprising a frame for the support and advancement of a plate on which there is at least one station for arrissing an edge of the plate, the arrissing station comprising an upper tangential grinding wheel and a lower tangential grinding wheel which have a working profile which is inclined at 45° with respect to the rotation axis of the grinding wheels and can engage respectively an upper edge and a lower edge of the plate being worked.

The present invention relates to a machine for removing the sharp edgein plates in general and in glass plates in particular.

BACKGROUND OF THE INVENTION

As is known, in the case of plates which are subject to cutting, sharpedges are formed which can be dangerous and consequently must beremoved.

Considering, merely by way of example, the case of glass plates,machines commonly known as arrissing machines are currently commerciallyavailable which are designed to remove part of the edge, thuseliminating the sharp arris.

Such removal operations are performed typically by means of diamondbelts which engage the arrises of the plate at a 45° angle with respectto the plane of the glass pane and move substantially at right angles tothe advancement of the plate.

Other known solutions use peripheral grinding wheels having a V-shapedtransverse cross-section, which allows to perform arrissingsimultaneously on both arrises of the edge.

Another known solution uses cup grinding wheels which work frontally andengage the arrises of the edge of the plate with an inclination ofsubstantially 45° with respect to the plane of the glass pane.

Generally, known solutions produce an irregular removal of the sharpnessof the arris along the entire length, a defect particularly observablein systems with a grinding wheel which is in a fixed position withrespect to the glass pane, since the sharp edge of the plate has alinearity error caused by the preceding cutting operation and most ofall there is a mismatch between the upper sharp edge and the lower sharpedge caused by the typical irregularity of glass plate cuttingoperations.

Another problem encountered with the solutions of the background art isdue to irregular removal at the end of the sharp edges, due to incorrectpositioning, during the initial step, of the abrasive element withrespect to the plate.

Moreover, known solutions suffer additional problems in case of a platethickness change, since only the abrasive belt is capable of adapting,within a certain interval, to the thickness variation.

Another problem further consists in that the grinding wheels that areused undergo localized wear, which creates considerable machiningvariations, and therefore it is necessary to perform adjustmentsfrequently.

SUMMARY OF THE INVENTION

The aim of the invention is to solve the problems described above byproviding a machine for removing the sharp edge in plates in general andin glass plates in particular, which allows to provide uniform andhomogeneous removal of the sharp edge on all arrises, thus obtaining asignificant increase in machining quality.

Within this aim, an object of the invention is to provide a machinewhich allows to increase considerably the machining speed while solvingthe problem of uneven wear of the grinding wheels that are used.

Another object of the present invention is to provide a machine which,thanks to its particular constructive characteristics, is capable ofgiving the greatest assurances of reliability and safety in use.

Still another object of the present invention is to provide a machinefor removing the sharp edge in plates in general and in glass plates inparticular which can be obtained easily starting from commonlycommercially available elements and materials and is also competitivefrom a merely economical standpoint.

This aim and these and other objects, which will become better apparenthereinafter, are achieved by a machine for removing the sharp edge inplates in general and in glass plates in particular, according to theinvention, comprising a frame for the support and advancement of a plateon which there is at least one station for arrissing an edge of saidplate, characterized in that said arrissing station comprises an uppertangential grinding wheel and a lower tangential grinding wheel, whichhave a working profile which is inclined with respect to the axis ofrotation of the grinding wheel and can engage respectively the upperedge and the lower edge of said plate.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention willbecome better apparent from the description of a preferred but notexclusive embodiment of a machine for removing the sharp edge in platesin general and in glass plates in particular, illustrated by way ofnon-limiting example in the accompanying drawings, wherein:

FIG. 1 is a schematic perspective view of the arrissing station for theedge of a plate with the main motor and the belt removed;

FIG. 2 is a schematic perspective view of the mutual arrangement of thetangential grinding wheels and of the plate;

FIG. 3 is a front elevation view, of the tangential grinding wheels inthe plate advancement direction;

FIG. 4 is a front view of the machine for removing the sharp edge;

FIG. 5 is a sectional view, taken along the line V-V of FIG. 4;

FIG. 6 is a sectional view, taken along the line VI-VI of FIG. 4;

FIG. 7 is a schematic perspective view, taken from the outer side, ofthe cantilever assembly which supports the corresponding tangentialgrinding wheel;

FIG. 8 is a top-up plan view of the cantilever assembly;

FIG. 9 is a perspective view, taken from the outer side, of thearrissing station with the motor means highlighted;

FIG. 10 is a schematic view of the arrissing station taken from theinner side, i.e., directed toward the plate advancement belt;

FIG. 11 is a top plan view of the arrissing station.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the figures, the machine for removing the sharp edgein plates in general and in glass plates in particular, generallydesignated by the reference numeral 1, comprises a frame 2 for thesupport and advancement of a plate 3 which is rested for example on abelt 4 which unwinds continuously.

At least one and preferably a plurality of arrissing stations, generallydesignated by the reference numeral 10, are typically provided at theedges of the plate.

Arrissing stations are usually provided on both of the advancement sidesof the plate, which has a rectangular shape, and moreover the lineprovides for two machines with an interposed 90° transfer system, sothat all the four edges of the plate are machined.

The drawing illustrates a single arrissing station, but of course, asmentioned earlier, the stations are typically four in number.

Each arrissing station 10 comprises an upper tangential grinding wheel11 and a lower tangential grinding wheel 12.

The grinding wheels have a machining or working profile 11 a and 12 awhich is inclined at 45° with respect to the axis of rotation.

Each grinding wheel can engage respectively the upper edge and the loweredge of the plate 3 being machined.

The grinding wheels 11 and 12 are supported by respective spindles, bothdesignated by the reference numeral 15, which are connected by means ofa cantilever support 16 with a vertical central shaft 17 which issupported by means of eyes 18 which are connected to the fixedstructure.

The shaft 17 has an upper pulley 19 which by means of a belt 20 drawsmotion from a driving pulley 21 which is connected to a main motor 22.

Each cantilever support can oscillate about the central axis 17 and ispushed to machine by means of a pusher, which is advantageously providedby means of a pneumatic cylinder 30, the piston 30 a whereof acts bypushing on the cantilever element so as to render active the sharp edgeof the corresponding grinding wheel.

Each cantilever element supports, rigidly associated with the shaft ofthe corresponding grinding wheel, an upper grinding wheel pulley 31 anda lower grinding wheel pulley 32 on which an upper grinding wheel belt34 and a lower grinding wheel belt 35 respectively unwind, said beltswinding around respective upper and lower central pulleys 36 and 37which are keyed on the central shaft 17 which draws motion from themotor 22.

With this type of connection, the grinding wheels are turned about theirown axis and the cantilever element is structured so as to move theinclined edges of the corresponding grinding wheels 11 and 12 so thatthey work the upper and lower arrises of the plate 3.

To allow uniform wear of the grinding wheel, there is provided a systemfor oscillating along a vertical direction, which comprises anoscillation motor 40 which is connected, for example by means of a nutscrew coupling 41, to the panel 42 which can slide with respect to theframe and supports the cantilever elements, imparting thereto areciprocating translational motion along the vertical axis, so that thepoint of the inclined working profile of the grinding wheels is changedin each instance.

With this arrangement, only the cantilever elements with thecorresponding spindles are moved, and, for this purpose the pulleys 36and 37 have an increased axial extension with respect to the width ofthe corresponding belt, so as to adapt to the variation in the placementof the pulleys 31 and 32 connected to the spindles 15.

This type of connection allows to have reduced moving masses, since themotors, due to the rotation of the grinding wheel and to the oscillationalong the vertical direction, remain in a fixed position.

To allow correct placement of the grinding wheels with respect to theedge of the plate, especially in the initial step, positioning cams areprovided which are constituted by an upper cam and by a lower cam, bothdesignated by the reference numeral 50, which engage an abutment roller51, which is associated with the respective cantilever element, so as toprovide an element for stopping the advancement of the grinding wheeltoward the plate, therefore providing exact positioning even in theinitial step of the engagement between the grinding wheel and the plate.

It should be added that the cam 50 arranged in an upper region can beconnected to a vertical positioning device, which is provided forexample by a piston 60 which changes the relative position of the cam 50arranged above according to the thickness of the plate.

With the apparatus described above, the plate to be worked is engaged bythe conveyor belt 4 and, during its advancement, encounters thearrissing stations, usually provided one for each side.

The lower spindle, with its grinding wheel turning, interferes with theplate to an extent which is preset by the contact of the cantileversystem which is adjusted by the arrangement of the cam 50.

Contact with the plate causes the movement of the spindle to thebalancing point between the grinding force and the force of thepneumatic cylinder that pushes the cantilever element so that the lowerarris of the edge is machined.

The plate, in its advancement, then encounters the upper spindle, whichmachines the upper sharp edge in the same manner described above.

When the plate abandons the spindles, the cantilever element moves thecam so that it abuts against the abutment roller and is positioned forsubsequent work.

During the working step, the spindles are made to oscillate in avertical direction so that contact between the grinding wheel and theplate occurs by utilizing the entire band, having a conical profile, ofthe tangential grinding wheel, so that uniform wear is obtained,minimizing the need for replacement or redressing of the grinding wheel.

From what has been described above it is evident that the inventionachieves the intended aim and objects, and in particular the fact isstressed that a machine is provided in which the sharp edge of the plateis arrissed by using two distinct tangential grinding wheels with a 45°contour, achieving uniform work thanks to the fact that such grindingwheels are supported by respective cantilever elements which allow toadapt the mutual positioning between the grinding wheel and the plate.

Another important aspect of the invention consists in that the controlmotors of the grinding wheels and of the vertical oscillation do notaffect the moving masses, which are constituted exclusively by thecantilever elements which are thus positioned correctly with respect tothe edge being worked thanks to the presence of the cam elements and ofthe constant thrust applied by the pneumatic pistons which keep thegrinding wheels in working contact against the edge.

The invention thus conceived is susceptible of numerous modificationsand variations, all of which are within the scope of the appendedclaims.

All the details may further be replaced with other technicallyequivalent elements.

In practice, the materials used, as well as the contingent shapes anddimensions, may be any according to requirements.

The disclosures in Italian Patent Application No. MI2006A001986 fromwhich this application claims priority are incorporated herein byreference.

What is claimed is:
 1. A machine for removing sharp edge in plates ingeneral and in glass plates in particular, comprising a frame for thesupport and advancement of a plate on which there is at least onestation for arrissing an edge of said plate, wherein said arrissingstation comprises an upper tangential grinding wheel and a lowertangential grinding wheel which have a working profile which is inclinedwith respect to a rotation axis of the grinding wheels and can engagerespectively an upper edge and a lower edge of said plate.
 2. Themachine according to claim 1, wherein said grinding wheels have aworking profile which is substantially inclined at 45° with respect tothe axis of rotation of the grinding wheels.
 3. The machine according toclaim 1, wherein said grinding wheels are supported so that they canrotate by spindles which are connected by means of a cantilever supportwith a vertical central shaft.
 4. The machine according to claim 3,wherein said cantilever supports are connected to said vertical centralshaft with the possibility to oscillate about said vertical centralshaft.
 5. The machine according to claim 3, further comprising means forturning said vertical central shaft which is functionally associatedwith said spindles.
 6. The machine according to claim 6, wherein saidmeans for turning said vertical central shaft comprise an upper pulley,which is keyed to said shaft and is functionally connected to a beltwhich engages a driving pulley, which is connected to a main motor whichis rigidly coupled to said support and advancement frame.
 7. The machineaccording to claim 3, further comprising, for each of said cantileversupports, a pusher which is adapted to push said tangential grindingwheels against the edge of the plate being worked.
 8. The machineaccording to claim 7, wherein said pusher is constituted by a pneumaticcylinder whose piston acts by pushing on said cantilever element.
 9. Themachine according to claim 3, wherein each of said cantilever elementssupports rotatably a shaft of the corresponding grinding wheel on whichan upper grinding wheel pulley and a lower grinding wheel pulley arekeyed respectively, said pulleys being connected respectively, by meansof an upper grinding wheel belt and a lower grinding wheel belt, to acentral upper pulley and a central lower pulley, which are keyed on saidcentral and vertical shaft.
 10. The machine according to claim 3,further comprising means for the oscillation of said cantilever elementsalong a substantially vertical direction.
 11. The machine according toclaim 10, wherein said oscillation means comprise an oscillation motor,which is supported by said frame and can be coupled by means of a nutscrew coupling to a panel which supports said cantilever elements. 12.The machine according to claim 9, wherein said upper central and lowercentral pulleys have a greater axial extension than said upper and lowergrinding wheel belts in order to compensate the oscillating motion alongsaid vertical direction.
 13. The machine according to claim 1, furthercomprising means for positioning the grinding wheels with respect to theedge of said plate with said grinding wheels disengaged from said edge.14. The machine according to claim 13, wherein said grinding wheelpositioning means comprise positioning cams which are constituted by anupper cam and a lower cam, which can be engaged by respective abutmentrollers which are associated with the respective cantilever element. 15.The machine according to claim 14, further comprising means forpositioning vertically said upper cam for adaptation to the thickness ofthe plate.